Swiss grinding innovations at the AMRC

August 5, 2016

The University of Sheffield Advanced Manufacturing Research Centre (AMRC) with Boeing is a world-class centre for advanced machining and materials research for aerospace and other high value manufacturing sectors.

With more than 80 member companies, this partnership between industry and academia has become a model for research centres worldwide.

Since 2013, the AMRC has targeted the development of a Grinding Centre of Excellence to complement the existing milling and turning capabilities that have been established within its machining group. As grinding and surface finishing operations can account for 20-25% of the cost on all machining operations, the Grinding Centre of Excellence’s vision is to extend and enhance its capability, both in terms of equipment and resource, to a level required by the existing partnership.

A major advancement in the AMRC Grinding Centre of Excellence’s development is the recent installation of a Studer S41 CNC universal cylindrical grinding machine supplied by Micronz, Studer’s sales representative in the North of England.

The AMRC’s technical fellow, Dr David Curtis explains: “Previously grinding has mainly been regarded as a means of machining for final dimensional accuracy and of achieving the workpiece’s required surface finish. However, through recently developed techniques which greatly increase material removal rates, this perception is rapidly changing.

“The AMRC’s grinding and surface finishing team have the capabilities and expertise to improve performance and quality across the range of grinding operations, with a particular focus on aerospace components. Process areas include cylindrical grinding, surface and profile grinding, multi-task grinding, hybrid grinding, gear grinding and mass finishing.

He continues: “To aid our research in these areas and to further enhance our grinding capabilities we began a search for a high-end cylindrical grinding platform in 2015. Having considered a couple of options, a visit to the Studer (part of the United Grinding Group) headquarters in Switzerland and a very successful demonstration of a Studer S41 CNC universal cylindrical grinding machine, convinced us that this was the answer to our needs.

“In addition to featuring a higher level of stability and precision than the alternatives we looked at, the S41’s multiple wheel-head capacity and overall flexibility, allowed it to cover the vast majority of our demanding needs.

“To enable the new S41 to not only accommodate all current workpieces, but also any larger, future work, we ordered the machine with an increased centre height of 325mm, allowing a swing of 650mm. We also specified the inclusion of high-speed grinding, thread grinding, out-of-round grinding, as well as a special high pressure coolant system that is suitable for use with emulsion and neat oil. The target was to specify a machine tool platform with research flexibility as well the ability to engage with a range of industrial applications.

“Our Studer machine is now actively engaged in a number of important projects including research into the grindability of materials and the study of automated process control for aerospace applications. Also, rather than users relying on the data supplied by the manufacturers of grinding wheels, we are currently looking to develop a standard wheel test to allow all grinding wheels to be benchmarked against each other. So far, although some other wheels have delivered good results, we have been particularly impressed with the high stock removal rates delivered by 3M’s Cubitron grinding wheels.

“As the United Grinding Group has become a Tier 1 Partner with the AMRC, our Studer S41 is also occasionally used as a demonstration resource for prospective Studer customers.”

The S41 is based around a Granitan S103 machine bed due to the advanced material’s excellent damping characteristics and favourable thermal behaviour. The large distance between the S41’s guideways and its rigidly constructed slides, provide further precision.

The machine features a wide range of advanced technical features such as high precision axis drives with linear motors, fast direct drive B-axis and a large selection of wheel-head variants. It lso features Studer’s innovative StuderGuide guideway system.

With a standard centre height of 225mm or 275mm and a distance between centres of 1,000mm or 1600mm, the latest generation CNC universal cylindrical grinding machine is able to efficiently undertake the vast majority of daily grinding tasks. The S41 can also be configured as a single purpose machine for large batch production use.

The use of the StuderWIN user interface and the StuderGRIND software module create a stable programming environment for the operator and further contribute to the machine’s efficiency.

A PC is integrated into the CNC control providing the ability to integrate in-process gauging and sensor technology for process monitoring. In addition, contact detection and automatic balancing systems in the control enable standardised programming of the different systems. Software for an internal loading system is also integrated in the control.